MPU-9150 View Datasheet(PDF) - Unspecified
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MPU-9150 Datasheet PDF : 50 Pages
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MPU-9150 Product Specification
Document Number: PS-MPU-9150A-00
Revision: 4.3
Release Date: 9/18/2013
Selection of the source for generating the internal synchronous clock depends on the availability of external
sources and the requirements for power consumption and clock accuracy. These requirements will most
likely vary by mode of operation. For example, in one mode, where the biggest concern is power
consumption, the user may wish to operate the Digital Motion Processor of the MPU-9150 to process
accelerometer data, while keeping the gyros and magnetometer off. In this case, the internal relaxation
oscillator is a good clock choice. However, in another mode, where the gyros are active, selecting the gyros
as the clock source provides for a more accurate clock source.
Clock accuracy is important, since timing errors directly affect the distance and angle calculations performed
by the Digital Motion Processor (and by extension, by any processor).
There are also start-up conditions to consider. When the MPU-9150 first starts up, the device uses its
internal clock until programmed to operate from another source. This allows the user, for example, to wait
for the MEMS oscillators to stabilize before they are selected as the clock source.
7.17 Sensor Data Registers
The sensor data registers contain the latest gyro, accelerometer, magnetometer, and temperature
measurement data. They are read-only registers, and are accessed via the serial interface. Data from these
registers may be read anytime. However, the interrupt function may be used to determine when new data is
available.
For a table of interrupt sources please refer to Section 8.
7.18 FIFO
The MPU-9150 contains a 1024-byte FIFO register that is accessible via the Serial Interface. The FIFO
configuration register determines which data is written into the FIFO. Possible choices include gyro data,
accelerometer data, temperature readings, auxiliary sensor readings, and FSYNC input. A FIFO counter
keeps track of how many bytes of valid data are contained in the FIFO. The FIFO register supports burst
reads. The interrupt function may be used to determine when new data is available.
For further information regarding the FIFO, please refer to the MPU-9150 Register Map and Register
Descriptions document.
7.19 Interrupts
Interrupt functionality is configured via the Interrupt Configuration register. Items that are configurable include
the INT pin configuration, the interrupt latching and clearing method, and triggers for the interrupt. Items that
can trigger an interrupt are (1) new data is available to be read (from the FIFO and Data registers); (2)
accelerometer event interrupts; and (3) the MPU-9150 did not receive an acknowledge from an auxiliary
sensor on the secondary I2C bus. The interrupt status can be read from the Interrupt Status register.
For further information regarding interrupts, please refer to the MPU-9150 Register Map and Register
Descriptions document.
For information regarding the MPU-9150’s accelerometer event interrupts, please refer to Section 8.
7.20 Digital-Output Temperature Sensor
An on-chip temperature sensor and ADC are used to measure the MPU-9150 die temperature. The readings
from the ADC can be read from the FIFO or the Sensor Data registers.
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